Low gas pressure alarm



Aug. 20, 1963 NVK. JENSEN 3,101,068?

LOW GAS PRESSURE ALARM Filed June 16, 1961 i 25 24 E; I 1| 10* 5' 34,

, INVENTOR. MgTnAN K JENSEN MM WM trite 3,101,058 Patented Aug. 20, 1963 thee 3,101,068 LDW GAS PRESSURE ALARM Nathan Kenneth Jensen, Minneapolis, Minn, assignor to Medic-Made, Inc, Minneapolis, Minn, a corporation of Minnesota Filed June 16, 1961, Ser. No. 117,611 9 Claims. (Cl. 116-70) This invention relates to a gas operated alarm device to signal the reduction of gas pressure below a desired minimum.

An object of my invention is the provision of a new and improved device of simple and inexpensive construction and operation for signalling the reduction of gas pressure to a level below a desired minimum.

Another object of my invention is to provide a novel device for allowing passage of a small amount of gas in response to the reduction of the pressure in a gas supply to a level below a predetermined minimum.

A further object of my invention is to provide an improved device which will withstand the effects of extremely high gaseous pressure and will further operate precisely in response to the reduction of gas pressure to a predetermined minimum to supply a small quantity of the gas for operating an audible alarm.

A still further object of my invention is to provide a new and novel device which is adjustable to operate in response to any of a wide range of low gas pressures for operating a signalling apparatus to indicate that the applied igas pressure has reduced to a preset minimum.

These and other objects and advantages of my invention will more fully appear from the following description made in connection with the accompanying drawings wherein like reference characters refer to similar parts throughout the severalviews and in which:

FIG. 1 is a perspective view illustrating the use of the present invention;

FIG. 2 is an enlarged longitudinal section view taken through the approximate center of the device;

FIG. 3 is a detail section view showing a portion of the apparatus illustrated in FIG. 2 and shown in shifted position, and

FIG. 4 is a detail plan view of the disc.

One form of the present invention is shown in the drawings and is described herein.

The device will be commonly employed with a source 11 of gas under high pressure and in the form shown the source 11 comprises a tank of conventional design with fittings within the cap 12 supplying gas under high pressure into a supply conduit 13 which may contain a valve 14. The device 10 is attached into the supplyconduit 13 as bya T -type fitting 15 and the device 10 has a boss or nipple 16 which may be attached into the T fitting 15. The supply an 11 may contain any of a number of various types of gases, and the gas may be pure oxygen or the gas may be nitrous oxide or various other gases which may be used in industrial or hospital installations. For instance, in a hospital, the supply tank 11 will be disposed in the operating room, and of course it is of the utmost important that the supply of gas be suflicient to last during the performance of an operation, and in the event that the quantity of gas in the supply tank 11 is depleted to a dangerous level during the course of an operation, the physician will certainly want to know of it so that steps can be taken to replace the gas supply tank with another supply. Frequently the pressures applied by the gas from the supply tank 11 may be in the range of 3100 p.s.i., and depending upon the size of the supply tank 11, it is desirable to produce an audible warning when the pressure in the supply tank 11 decreases to 100 p.s.i. or 60 p.s.i.. In

the case of a large tank, ample warning is provided by producing an indication of 60 p.s.i. in the tank, because sulficient gas remains in the tank so as to permit changing to another tank. In a smaller tank, it may be desired to produce a warning when the pressure decreases to p.s.i. so as to give ample time to change to a new supply before the supply being used is completely exhausted or depleted.

It will therefore be seen that in order for the gas pressure detecting and indicating device 10 to be effective, it must be capable of withstanding extremely high gas pressure, in the range of 3100 p.s.i., but to operate consistently when gas pressure being applied thereto, decreases to the range to 60 to 100 p.s.i. The operation must be positive and accurate and in response to the lower pressures.

The gas pressure detecting and indicating device 10 includes a housing 17 which includes a forward wall portion 18 and a rear cover 19 which is apertured at 20 to exhaust gas from the internal gas outlet compartment 21. The forward wall and rear cover 19 are removable, but are normally secured to the body portion 17a of the housing by screws 22.

Flow of gas through the outlet compartment causes a response by the gas flow detecting and indicating or alarm device 23 which generally obstructs flow of gas through the outlet compartment 21 but permits limited gas flow through one or more slot apertures 24 therein. In the slot apertures 24 are disposed vibrating needs 25 which responds to gas flow over an extremely wide range of gas flow velocities and produce an audible indication or signal which can be heard anywhere in the vicinity of the device 10. Preferably, the sound will have a distinctive tone so that the operation of this gas flow detecting and indicating device can be distinguished from other noises that may be in the vicinity.

The housing 17 also includes a partition structure indicated in general by numeral 26 and includes a rear wall 27 which is spaced from the forward wall 18 to define an internal chamber 28 which is rather shallow in depth as compared to its circular diameter. The rear wall 27 has a central threaded opening 259 therethrough and also has a gas passage opening or aperture 29a therethrough adjacent the opening 29 and communicating between the internal chamber 2 8 and the outlet compartment 21.

The rear wall 27 has a forwardly facing and generally annular disc-supporting surface 30 which defines the rear side of the internal chamber 28 andwhich has an outer periphery 31 lying in a common plane. The inner periphery 32. of the annular surface 30* is disposed very slightly rearwardly of the outer periphery 31. 1n the sepcific form shown, the annular surface 30 is slightly comically tapered, and converges in a rearward direction; the taper of the annular and slightly conical surface 30 is approximately 2 to the plane of the outer periphery 31.

The partition structure 26 also includes a cup or sleeve 33 which is threaded into the opening 29 and which has a closed rear end 34 projecting into the outlet compartment 21, and also has an open forward end 34a slidably mounting a valve seat element 35 which is preferably constructed of a slightly resiliently yieldable material such as a plastic known as Teflon. It will be seen that the open forward end of the mounting sleeve 33 has an inturned edge or lip 36 which limits the forward sliding movement of the valve seat element 35. The valve seat element 35 is normally resiliently urged forwardly by a coil spring 36a disposed within the cup or sleeve 33.

It will be seen that normally, the front surface of the valve seat element 35 is disposed in close proximity with the position of the inner periphery 32 of the annular discdisc 37 and the forward wall 18.

supporting surface 3h, but the normal position of the 37 and the front wall 13 to preventpassage of any gas around the outer periphery of the disc, and to maintain the disc in spaced relation with the front wall 18. The

. disc 37 also has a small central aperture 38 and a rearwardly projecting annulus 39 with a rearwardly facing annular sharpened edge for engaging the valve seat clement 35 in gas-sealing relation when the disc 37 is flexed under influence of gas pressure supplied through the inlet opening 39a which communicates through the nipple l6 and the front wall 13 and into the chamber 28.

In the relaxed condition or the device 10', the disc 37 will be in the position shown in FIG. 2. Gas under low pressure would be permitted to flow from the inlet, through the aperture 38 and through the internal chamher 28, through the gas passage aperture 29a and through the opening 24 and outwardly through the apertures 20. It the-re is sufiicient flow of gas, the reeds will vibrate and produce an audible signal. When the gas pressure of approximately 3100 p.s.i. from the supply tank 11 is applied in the conduit 13 and in the inlet 39a of the device 19), substantially the entire disc is subjected to the gas pressure because of the spaced relation between the Under influence of this high gas pressure, the disc'will flex slightly rcarwardly into the position shown in FIG. 3 wherein substantially the entire disc 37 is supported on the annular and slightly tapered disc-supporting surface of the rear wall 27, with the exception of a small central area opposite the opening 29. When the disc 37 is flexed rearwardly as shown in FIG. 3, the rearwardly projecting annulus 39 will engage the forward end of the Teflon valve seat element and seating portions of the annulus and of the element 35 will engage each other in gas pressure-sealing relation. The size of the aperture 38 is extremely small so that even though the gas pressure applied through the aperture 33 is very substantial, the actual force applied against the valve seat element 35 is relatively small. The flexing of the disc will cause actual rearward movemerit of the valve seat element 35, away from the in turned lip 36, substantially as shown in FIG. 3. Of course the valve seat element 35 is continuously urged forwardly to maintain sewing relation with the rear- ;wardly projecting annulus of the disc by means of the spring 36a. As a result of the sealing relation between the disc and the valve seat element there will be no flow of gas through the aperture 2% or through the outlet compartment 21. I

Gradually as the gas from the supply tank 11 is used, the pressure therein will diminish. As the gas pressure diminishes, the force applied against the disc 37 decreases, and when the gas pressure decreases to a predetermined level, the resiliency of the disc 37 will cause the disc to start to return to its normal fiat condition as shown in FIG. 2. As the disc starts to return to its normal position the disc will move away slightly from the surface 30 and the annulus 39 will retract slightly, and under these conditions, the valve seat element 35 is pressed forwardly by the coil spring 36:: to maintain the sealed relation between the disc and the valve seat element.

As the pressure against the disc continues to decrease, the disc will continue to flex forwardly to its normal position and eventually the valve seat element 35 will ongage the inturned lip 36 which restricts further forward movement of the valve seat element. Continued return of the disc 37 to its normal position causes the annulus 39 to pull away from the front face of the valve seat element, which allows gas flow therebetween. As soon as any gas flow occurs at this point, the pressure on 0pposite sides of the disc 37 is substantially equalized and the disc 37 will quickly return to its normal position as seen in FIG. 2 which causes the gas to flow quickly through the aperture 33 and through the opening 2% for operating the reed 25 which produces an audible signal.

If it is desired to change the low pressure at which the disc allows gas flow through the device It) to operate the reed 25, the position of the sleeve or cup 33 is adjusted'so as to move the inturned lip 36 forwardly or rearwardly. If the cup 33 is turned so that the normal position of the valve seat element 35 is closer to the disc, and so that the inturned lip 36 is disposed farther forwardly from that shown in FIG. 2, then the flow of gas through the device It) will be obstructed down to a lower pressure than was heretofore necessary. In other words, if the reed 25 made an audible signal at 1700 p.s.i. with the adjustment shown in FIG. 2, movement of the inturned lip 36 and the valve seat element 35 toward the disc by turning the cup 33 will cause the operation of the reed 25 at approximately 60 or 75 p.s.i. This occurs because the disc will remain in sealing engagement with the valve seat element 35 as the disc progressivcly returns to its normal position.

It will, of course, be understood that various changes may be made in the form, details, arrangement and proportions of the parts without departing from the scope of my invention which consists of the matter shown and described herein and set forth in the appended claims.

What I claim is:

1. A'device for detecting and indicating decrease of gas pressure in a gas supply below a desired level, said device comprising a housing having forward and rear ends and having a gas outlet in said rear end, said housing including a forward end wall with a gas inlet therethrough and means adapted for attaching said inlet to the gas supply, a partition structure between said outlet and said forward end wall and spaced from said forward end wall to define an internal chamber thercbetween, said partition structure being disposed at the rear side of said chamber and having a recess in the center thereof, said partition structure defining a forwardly facing and generally annular discsupporting surface having an inner periphery adjacent said recess and having an outer periphery, said outer periphery lying in a commonplane and said inner periphery being disposed slightly re'arwardly of said outer periphery, a forwardly facing valve seat element in the recess and being slidable forwardly and rearwardly therein, a stop in the ward said stop and toward said chamber, said partition structure having an aperture therein communicating between said chamber and said gas outlet, a resilient disc in said chamber and having an outer periphery lying against the outer periphery of said disc-supporting surface and said disc also having a central portion in spaced relation with said forward wall and with said partition structure, the spacing between the central portion of the disc and said disc-supporting surface being sufiiciently small as to permit resilient flexing of the disc into engagement with said surface without cxceedin g the elastic limits of the disc, the outer periphery of the disc being sealed to the housing to prevent gas flow past the disc outer periphery, the disc having a central aperture aligned with said valve seat element, said valve seat element and said disc having aligned seating portions around the periphery of said central aperture and engageable with each other in gas-sealing relation when the disc is flexed under the influence of high gas pressure at the inlet, and gas flow detecting and indicating means in said outlet.

2. The invention set forth in claim 1 wherein said stop is adjustable in a fore-and-aft direction and toward and away from said chamber for varying the forward limit of movement of the valve seat element and varying the pressure at which said disc and valve seat element separate from each other for following gas flow through the outlet and operating said detecting and indicating means.

3. A device for detecting and indicating decrease of gas pressure in a gas supply below a desired level, said device comprising a housing having forward and rear ends and having a gas outlet in said rear end, said housing including a forward end wall with a gas inlet therethrough and means adapted for attaching said inlet to the gas supply, a partition structure between said outlet and said forward end wall and spaced from said forward end wall to define an internal chamber therebetween, said partition structure being disposed at the rear side of said chamber and having a recess in the center thereof, said partition structure defining a forwardly facing and generally annular disc-supporting surface having an inner periphery adjacent said recess and having an outer periphery, said outer periphery lying in a common plane and saidinner periphery being disposed slightly rearwardly of said outer periphery, a forwardly facing valve seat element in the recess and being slidable forwardly and rearwardly therein, a stop in the recess limiting forward movement of said element, spring means continuously urging said element forwardly toward said stop and toward said chamber, said partition structure having an aperture therein communicating between said chamber and said gas outlet, a resilient disc in said chamber and having an outer periphery lying against the outer periphery of said disc-supporting surface and said disc also having a central portion in spaced relation with said forward wall and with said partition structure, the spacing between the central portion of the disc and the disc-supporting surface being sufiiciently small as to permit resilient flexing of the disc into engagement with said surface without exceeding the elastic limits of the disc, the outer periphery of the disc being sealed to the housing to prevent gas flow past the outer periphery of the disc, the disc having a central aperture aligned with said valve seat element, said valve seat element and said disc having aligned and mutually engageable seating portions around the periphery of said aperture, one of said seating portions comprising an annulus projecting toward the other seating portion and surrounding the aperture and being engageable with the other of said seating portions in gas-sealing relation when the disc is flexed under the influence of high gas pressure at the inlet, and the gas flow detecting and indicating means in said outlet.

4. The invention set forth in claim 3 wherein the other of the seating portions opposite to the annulus is conitructed of resiliently deformable material for receiving the projecting annulus in gas-sealing relation therewith.

5. The invention set forth in claim 3 wherein said annulus is formed integrally of said disc and projects rearwardly therefrom into proximity with said valve seat element for movement into sealing engagement with the seating portion of said valve seat element in gas-sealing relation and to move the valve seat element rearwardly when the disc is flexed tinder the influence of high gas pressure at the inlet and when the disc lies flush against said discsupporting surface.

6. The invention set forth in claim 5 wherein said annulus has an annular rearwardly facing sharpened edge engageable with the seating portion of the valve seat element with a substantial localized pressure to produce thorough sealing between the disc and valve seat element.

7. The invention set forth in claim 5 wherein said valve seat element is constructed of resiliently deformable material to yield slightly under the pressure exerted thereagainst by the annulus and provide a tightly sealing relation therewith to restrict passage of gas under pressure.

8. A device for detecting and indicating decrease of gas pressune in a gas supply below a desired level, said device comprising a housing having forward and rear ends and having a gas outlet in said rear end, said housing ineluding 'a forward end wall with the gas inlet therethrough and means for attaching said inlet to the gas supply, a partition structure between said outlet and said forward end wall and spaced from said forward end wall to define an internal chamber therebetween, said partition structure being disposed at the rear side of said chamber and having a recess in the center thereof, said partition structure defining a forwandly facing and generally annular disc-supporting surface with a slightly tapered conical shaped contour converging in a rearward direction, said dise-supportin g surface having an inner periphery adjacent said recess and having an outer periphery, a forwardly facing valve seat element in the recess and being slidable forwardly and rearwardly therein, a stopin the recess limiting forward movement of said element, spring means continuously urging said element forwardly toward said stop and toward said chamber, said partition structure having an aperture therein communicating between said chamber and said gas outlet, a resilient disc in said chamber and having 'a-n outer periphery lying against the outer periphery of said disc-supporting surface, a resilient sealing ring disposed between and engaging the outer periphery of said disc supporting surface and said forward end wall of the housing to prevent gas flow past the outer periphery of the disc and to maintain a spaced relation between the disc and said front end wall and said disc also having a central portion in spaced relation with said forward Wall and with said partition structure, the spacing between the central portion of the disc and the disc-supporting surface being sufiiciently small as to permit resilient flexing of the disc into engagement with said surface without exceeding the elastic limits of the disc, the disc having a central aperture aligned with said valve seat element, said valve seat element and said disc having aligned seating portions around the periphery of said aperture and engageable with each other in gas-sealing relation when the disc is flexed under the influence of high gas pressure at the inlet, and gas flow detecting and indicating means in said outlet.

9. A device for detecting and indicating decrease of :gas pressure in a gas supply below a desired level, said device comprising a housing having forward and rear ends and having an enlarged gas outlet compartment in said rear end, said housing including a forward end wall with a gas inlet therethrough and means adapted for attaching said inlet to the gas supply, the housing also having a rear wall between said outlet compartment and said forward end wall and spaced from said forward end wall to define an internal chamber therebetween, said rear wall being disposed at the rear side of said chamber and having an opening in the center thereof, said rear wall defining a forwardly facing and generally annular discsupporting surface having 'a slightly tapering conical contour converging in a rearward direction, said disc-supporting surface also having an inner periphery adjacent said opening therein and also having an outer periphery, a forwardly facing valve seat element in said opening of the rear wall and being slidable forwardly and rearwandly therein, a valve seat clement-m ounting cup threaded into the opening of the rear wall and having :a rearwardly extending closed end projecting into the outlet compartment and said cup also having an open end facing forwardly toward said chamber and having an inturned lip on said open end retaining the valve seat in the cup and limiting the forward sliding movement of the valve seat element, a spring in the cup urging the valve seat element forwardly against said lip and toward said internal ehamber, the rear wall having a gas discharge aperture communicating between said internal chamber and said outlet compartment, a resilient disc in said chamber and having an outer periphery lying against the outer periphery of said disc-supporting surface and said disc also having a central portion in spaced relation with said forward wall I 7 and with said rear wall, the spacing between the central portion of the disc and the disc-supporting surface being sufficiently small as to permit resilient flexing of the disc into engagement with said surface Without exceeding the elastic limits of the disc, a resilient sealing ring disposed between the outer periphery of the disc and the forward to prevent gas flow past the outer periphery of the disc and to maintain the disc in spaced relation with the fiorward wall, the disc also having :a central aperture aligned With said valve seat element, said valve seat element and said disc having aligned seating portions around the periphery of said aperture in the disc and being engageable with each other in gas-sealing relation when the disc is flexed under theinfluence of high gas pressure at the inlet to prevent passage of gas through the disc 5 aperture, and gas flow detecting and indicating means in 1 said outlet compartment.

References Cited in the file of this patent UNITED STATES PATENTS Spadola Dec. 25, 1951 2,893,343 Judd .a July 7, 1959 

1. A DEVICE FOR DETECTING AND INDICATING DECREASE OF GAS PRESSURE IN A GAS SUPPLY BELOW A DESIRED LEVEL, SAID DEVICE COMPRISING A HOUSING HAVING FORWARD AND REAR ENDS AND HAVING A GAS OUTLET IN SAID REAR END, SAID HOUSING INCLUDING A FORWARD END WALL WITH A GAS INLET THERETHROUGH AND MEANS ADAPTED FOR ATTACHING SAID INLET TO THE GAS SUPPLY, A PARTITION STRUCTURE BETWEEN SAID OUTLET AND SAID FORWARD END WALL AND SPACED FROM SAID FORWARD END WALL TO DEFINE AN INTERNAL CHAMBER THEREBETWEEN, SAID PARTITION STRUCTURE BEING DISPOSED AT THE REAR SIDE OF SAID CHAMBER AND HAVING A RECESS IN THE CENTER THEREOF, SAID PARTITION STRUCTURE DEFINING A FORWARDLY FACING AND GENERALLY ANNULAR DISCSUPPORTING SURFACE HAVING AN INNER PERIPHERY ADJACENT SAID RECESS AND HAVING AN OUTER PERIPHERY, SAID OUTER PERIPHERY LYING IN A COMMON PLANE AND SAID INNER PERIPHERY BEING DISPOSED SLIGHTLY REARWARDLY OF SAID OUTER PERIPHERY, A FORWARDLY FACING VALVE SEAT ELEMENT IN THE RECESS AND BEING SLIDABLE FORWARDLY AND REARWARDLY THEREIN, A STOP IN THE RECESS LIMITING FORWARD MOVEMENT OF SAID ELEMENT, SPRING MEANS CONTINUOUSLY URGING SAID ELEMENT FORWARDLY TOWARD SAID STOP AND TOWARD SAID CHAMBER, SAID PARTITION 